Development and Characteristics of a Kleingrass Population with Reduced Post-Harvest Seed Dormancy1
- C. R. Tischler and
- B. A. Young2
Kleingrass (Panicum coloratam L.) seed has a period of postharvest dormancy lasting approximately 0.5 yr. Six cycles of recurrent selection (selecting seedlings germinating within 3 days) for reduced post-harvest dormancy were used to generate a plant population (LD-6) in which germination of freshly harvested seed was approximately 90%, compared to 5 to 20% for unselected material. Four germination treatments (light, light-acid, dark, dark-acid) were applied to LD-6, fresh dormant (non-afterripened), and 1-year-old dormant seed (afterripened) at three temperature regimes (35/25°C, 25/15°C, and 40°C). Germination counts for the light treatments were continued for 27 days. Germination counts for the dark treatments were made only at 6 days. Comparisons of data from light- and dark-grown treatments were based on total germination percentages at Day 6 only, while comparisons of light treatments were based on data for the entire 27-day counting period. The LD-6 seed performed similarly (but with higher germination percentages) afterripened seed (27-day count) at all germination temperatures. Rankings of the three seedlots were the same at all temperatures in the light, with germination of LD-6 being the highest and that of non-afterripened being the lowest. Rankings were also consistent across temperatures for the acid treatments. Acid treatments significantly improved germination in all cases except for the afterripened seedlot at the alternating temperatures and LD-6 at 25/15°C. In most cases for the light and light-acid treatments, germination of seedlots was highest at 35/25°C and lowest at 40°C. Germination was uniformly low in darkness, but germination of dark-acid treatments was normally higher than that of light treatments (6-day counts). Coefficients of velocity (data from 27 days) were calculated as an index of rapidity of germination. In all cases, acid treatments had higher coefficients of velocity. Coefficients of velocity for LD-6 were similar to those for the afterripened seedlot, indicating that selection for reduced dormancy did not increase speed of germination.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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